A tip for mpeg2dec-0.4.0 on x86_64

Ryan Twitchell tryan2 at rochester.rr.com
Sun Nov 6 13:09:28 PST 2005


I'm posting this so that if anyone else has the same problem, they will 
hopefully find this message in the archives. I guess this would be the 
best place to post this... maybe we need a new list: XBLFS!

mpeg2dec-0.4.0 compiled ok on my pure64 machine but failed testing
with some scary messages about push, pop, and mov assembly instructions.
The failure comes as a result of optimizations set up in the file 
cpu_accel.c for x86 processors. What effect this would have on actually 
using the library after install I did not bother to find out.

The following link is what helped me find a fix. The patch near the top 
of the page isn't quite right for the 0.4.0b version of libmpeg2. I just 
added #undef ACCEL_DETECT near the top of the concerned file 
(cpu_accel.c), and that seemed to do the trick. I didn't try to modify 
the optimizations to match my processor like in the link below, as I 
barley understand C, let alone assembly on a 64-bit processor. Hopefully 
it won't result in *too* much of a performance hit.

http://sourceforge.net/mailarchive/forum.php?forum_id=729&max_rows=25&style=nested&viewmonth=200412

I get to watch movies now!
	Ryan




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